For me traditional 4x games such as Civ 5 can be great fun in the early stages, but suffer very heavily from micromanagement overload as your kingdom size increases. Usually by the time you reach the middle stages of the game it's all over bar the shouting from a competitive point of view, but it's a very drawn out process getting the AI to lie down and die.

Paradox haven't solved this problem entirely yet (we'll have to see in EU4), but it's not nearly so acute, because the economy is much more concentrated and to take CK2 (their most recent game) as an example: As you progress through the game you also (if you play for territory) progress up the county/duchy/kingdom/empire hierarchy. The clever mechanics in the game mean that you can only control the vassals directly beneath you in the hierarchy. And since you also restricted in the size of your "demesne" i.e the territories you can directly control, micromanagement is much reduced.